Conundrum Cubed is a jumping puzzle located in Mount Maelstrom. You’ll find it in the northwest corner, north of the Govoran waypoint.
Head north into the Cubular Fells cave.
After running into the cave, you’ll see what looks like the below image. Work your way up on the right side until you get to the cube pointed out by the second arrow. Stop here, as the next couple of cubes have spike traps on them — if you get hit by those without stability, you will tumble off and likely die. Keep an eye on all cubes before you jump, as most of them have these traps. The second image indicates that you jump onto the branch and step into the blue portal, which will teleport you to another location in this cave.
After going through the first portal, you’ll end up below; run across the thick branch and jump down below where you’ll see two traps. Avoid getting hit by those, as they might send you off the side, causing you to die. Go into the only blue portal you see to be teleported to the next location.
Once teleported, you’ll see this. Jump across the cubes and make it to the other side — but be careful, there are spike traps on these cubes. Use the blue portal in the image.
Next you’ll end up here. Jump down to the two portals here, and step into the first one (if it doesn’t trigger, you may need to go in between both the first and second, but no farther than that).
Lastly, you’ll see this. Hop onto the non-spike trapped cube, then run past the first portal. Be careful not to keep running, or the second portal will send you back a bit. Just step in between the two and stop there for a moment.
Now claim your well-deserved reward!